An embodiment of the invention provides for Doppler sensor monitoring of pipe and flow conditions of a pipeline for flowing hydrocarbon mixtures. More specifically, but not by way of limitation, in an embodiment of the present invention, one or more Doppler sensors may be configured to sense a profile through a section of the pipeline that may be provided to a processor that may compare the profile with previous profiles through the section of pipeline to determine depositing on and/or corrosion to the section of pipeline. Doppler output from the sensor regarding the flow of the hydrocarbon mixture may be combined with the profile for analysis of deposits and/or corrosion and/or to provide for the management of the sensing of the section of the pipeline by the Doppler sensor. In some embodiments, a network of Doppler sensors may be configured to provide for flow assurance and/or monitoring of pipe condition in a pipeline transporting hydrocarbons, and in particular, but not by way of limitation, a network of noninvasive sensors whose output is data-fused to determine properties of the pipeline and flow through the pipeline. In certain aspects the network of Doppler sensors may further comprise acoustic impedance sensors and/or thermal probe sensors.
Pipe condition monitoring, flow condition monitoring and flow assurance are important in oilfield production systems, particularly subsea systems with long tiebacks, and hydrocarbon transportation pipelines. In such production systems and pipelines, various scale depositions may occur in part or all of the pipeline, production conduits or the like during the life of a production well or a transportation pipeline. These scale deposits may be the principle causes of flow assurance problems.
The term scale may be used to describe various organic and mineral deposits on the pipe wall, such as asphaltenes, waxes, hydrates or the like. Wax and asphaltene depositions, due to the cooling effect of seawater, may be a main concern for sub-sea tieback systems. Mineral scales may be associated with production pipelines and the like being caused by water breakthrough during production. Currently scale inhibition and/or remediation strategies may only be based on laboratory analysis of fluids retrieved from the production systems and transportation pipelines. The information from such analysis may be of limited value because it is not conducive to real-time understanding and management. Furthermore, In the case of remediation management, the current flow and pipeline analysis systems provide no feedback information on the effect of the remediation treatment. This may lead to productivity decrease due to under-treatment or undue treatment cost due to over treatment.
Pipeline corrosion is an important issue for production and transportation systems. For example, if sand erosion or the like occurs during oil production, then there is a significant possibility of sand damage to any anti-corrosion coatings that may have been applied inside the pipes, conduits and/or the like of the oil production or oil transportation systems. As such, this sand damage to the oil production or oil transportation systems may lead to corrosion of the pipes and/or conduits of the oil production or oil transportation systems. Moreover, serious corrosion should be detected and repaired in time to prevent accidental occurrences, such as hydrocarbon spills or the like, which may be extremely significant in subsea or remote locations. Other applications of flow assurance and pipeline monitoring include the detection of abnormal conditions in the production or transportation of hydrocarbons. For example, in a subsea gas production system, liquid may accumulate and produce slug flow conditions that may overload a surface handling system. An early warning system as to the arrival time of such slugs may allow timely control measures to be taken to prevent system overloading. A real time monitoring system on the seabed pipeline may also detect events such as water breakthrough long before it reaches the surface facility.
U.S. Pat. No. 6,758,100 (“the '100 patent”) describes a clamp-on ultrasonic multiphase flow meter based on range-gated (pulsed) Doppler measurements. In the '100 patent, Doppler data is used to derive flow velocities and phase fractions. The entire disclosure of the '100 patent is hereby incorporated by reference for all purposes.
U.S. Pat. No. 6,575,043 (“the '043 patent”) describes a non-invasive clamp-on multi-phase flow meter based on an acoustic impedance measurement principle. Identification of liquid and gas phases inside the pipe in the '043 patent is achieved by measuring the acoustic impedance of the material in contact with the pipe wall, and a velocity measurement is performed by cross-correlating impedance signals from two measurements separated by a known distance along the axial direction of the pipe. The entire disclosure of the '043 patent is hereby incorporated by reference for all purposes.